Producing diolefins.



UNITED STATES PATENT OFFICE.

FRANZ WEBEL, 0F MANNHEIM, GERMANY, ASSIGNOR T0 BADISCHE ANILIN 8a SODAFABRIK, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, A CORPORATION.

PRODUCING DIOLEFINS.

No Drawing.

Patented May 14, 1912.

To all whom it may concern Be it known that I, FRANZ WEBEL, subject ofthe King of Bavaria, residing at Mannheim, Germany, have invented newand useful Improvements in Producing Diolefins, of which the followingis a specification.

In the J ownal fi'ir Pralctz'sche Chemz'e (2), Vol. 55, page 5,Ipatiefi' has described the production of a particular diolefin, viz. ofisoprene, by heating dibrom-isopentane with alcoholic potash. I havefound, however, that I can obtain much better yields of diolefins byheating a monohalogenated monohydric alcohol with a solid compound whichis capable of catalytically splitting ofi halogen hydrid and water. Asan instance of a compound which can be employed for thus splitting ofi'halogen hydrid and water, I mention alumina. The reaction is preferablycarried out by passing a monohalogenated monohydric alcohol in the stateof vapor through a tube or the like containing the heated solid reagent,and it is also advantageous to carry out the reaction under reducedpressure. The tube containing the alumina, or the like, may, forinstance, be from about 1 to 3 yards inlength.

The process of my invention is of particularadvantage for the productionof diolefins which can be employed in the production of artificialcaoutchouc and similar bodies, for instance, diolefins which containfour, five, or six carbon atoms.

In this invention the esters of the monohalogenated monohydric alcoholsare equivalent to the alcohols themselves. 1

The following examples will serve to illustrate further the nature of myinvention, which, however, is not confined to these examples. The partsare by weight. 1

Example 1: Pass vaporized trimethylethylene-glycol-chlorhydin (0H,) 0(ID-OH (OH) .CH,,,

of a boiling point of from 138 to 142 (3., over alumina heated to 350C., while employing a pressure of 18 millimeters. The distillatecontains methyl-is0propyl-ketone and isoprene.

Example 2: Pass vaporized acetic ester of 3-brom 2-methyl-butanol- (1)over alumina at 30 millimeters pressure and at- 400 C., whereupon aceticacid, hydrobromic acid and isoprene are obtained.

Now what I claim is 1. The process of producing diolefins by heating amonohalogenated monohydric alcohol with a solid compound which is ca;pable of catalytically splitting ofi' halogen hydrid and water.

2. The process of producing diolefins by heating a monohalogenatedmonohydric alcohol under reduced pressure with a solid compound which iscapable of catalytically splitting ofl halogen hydrid and water.

3. The process of producing isoprene by heatingtrimethyl-ethylene-glycol chlorhydrin with alumina.

4. The process of producing isoprene by heatingtrimethyl-ethylene-glycol chlorhydrin with alumina under reducedpressure.

5. The process of producing isoprene by passing vaporizedtrimethyl-ethylene-glycol -chlorhydrin at a pressure of from 15 to 20millimeters over alumina at a temperature of from 340 to 360 C.

,In testimony whereof I have hereunto set my hand in the presence of twosubscribing witnesses.

FRANZ WEBEL.

Witnesses:

J. ALEG. LLoYn, A. O. TI'I'IMANN.

